A.A subquery should retrieve only one row.
B.A subquery can retrieve zero or more rows.
C.A subquery can be used only in SQL query statements.
D.Subqueries CANNOT be nested by more than two levels.
E.A subquery CANNOT be used in an SQL query statement that uses group functions.
F.When a subquery is used with an inequality comparison operator in the outer SQL statement, the column list in the SELECT clause of the subquery should contain only one column.
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Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables:
EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2(25)
LAST_NAME VARCHAR2(25)
HIRE_DATE DATE
NEW_EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
NAME VARCHAR2(60)
Which UPDATE statement is valid?（）
A.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployeesWHEREemployee_id=180）WHEREemployee_id=180；
B.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployees）WHEREemployee_id=180；
C.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployeesWHEREemployee_id=180） WHEREemployee_id=（SELECTemployee_idFROMnew_employees）；
D.UPDATEnew_employeesSETname=（SELECTlast_nameFirst_nameFROMemployeesWHEREemployee_id=（SELECTemployee_idFROMnew_employees） WHEREemployee_id=180；
A.USER_CONSTRAINTS
B.USER_OBJECTS
C.ALL_CONSTRAINTS
D.USER_CONS_COLUMNS
E.USER_COLUMNS
A.cannot be nested
B.manipulate data items
C.act on each row returned
D.return one result per row
E.accept only one argument and return only one value
F.accept arguments which can be a column or an expression
Evaluate this SQL statement:
e.employee_id, (.15* e.salary) + (.5 * e.commission_pct)
+ (s.sales_amount * (.35 * e.bonus)) AS CALC_VALUE
FROM employees e, sales s
WHERE e.employee_id = s.emp_id;
What will happen if you remove all the parentheses from the calculation?（）
A.The value displayed in the CALC_VALUE column will be lower.
B.The value displayed in the CALC_VALUE column will be higher.
C.There will be no difference in the value displayed in the CALC_VALUE column.
D.An error will be reported.
Examine the structure of the EMPLOYEES table:
Column name Data type Remarks
EMPLOYEE_ID NUMBER NOT NULL, Primary Key
EMP_NAME VARCHAR2(30)
JOB_ID VARCHAR2(20) NOT NULL
SAL NUMBER
MGR_ID NUMBER References EMPLOYEE_ID column
DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column
of the DEPARTMENTS table
You need to create a view called EMP_VU that allows the users to insert rows through the view. Which SQL statement, when used to create the EMP_VU view, allows the users to insert rows?（）
A.CREATE VIEW emp_vu AS SELECT employee_id, emp_name, department_id FROM employees WHERE mgr_id IN (102, 120);
B.CREATE VIEW emp_vu AS SELECT employee_id, emp_name, job_id, department_id FROM employees WHERE mgr_id IN (102, 120);
C.CREATE VIEW emp_vu AS SELECT department_id, SUM(sal) TOTALSAL FROM employees WHERE mgr_id IN (102, 120) GROUP BY department_id;
D.CREATE VIEW emp_vu AS SELECT employee_id, emp_name, job_id, DISTINCT department_id FROM employees;
A.A WHERE clause can be used to restrict both rows and groups.
B.A WHERE clause can be used to restrict rows only.
C.A HAVING clause can be used to restrict both rows and groups.
D.A HAVING clause can be used to restrict groups only.
E.A WHERE clause CANNOT be used in a query if the query uses a HAVING clause.
F.A HAVING clause CANNOT be used in subqueries.
A.The tables being joined have NOT NULL columns.
B.The tables being joined have only matched data.
C.The columns being joined have NULL values.
D.The tables being joined have only unmatched data.
E.The tables being joined have both matched and unmatched data.
F.Only when the tables have a primary key-foreign key relationship.
You need to create a table named ORDERS that contains four columns:
1.an ORDER_ID column of number data type
2.a CUSTOMER_ID column of number data type
3.an ORDER_STATUS column that contains a character data type
4.a DATE_ORDERED column to contain the date the order was placed
When a row is inserted into the table, if no value is provided for the status of the order, the value PENDING should be used instead.
Which statement accomplishes this?（）
A.CREATE TABLE orders ( order_id NUMBER(10), customer_id NUMBER(8), order_status NUMBER(10) DEFAULT 'PENDING', date_ordered DATE );
B.CREATE TABLE orders ( order_id NUMBER(10), customer_id NUMBER(8), order_status VARCHAR2(10) = 'PENDING', date_ordered DATE );
C.CREATE OR REPLACE TABLE orders ( order_id NUMBER(10), customer_id NUMBER(8), order_status VARCHAR2(10) DEFAULT 'PENDING', date_ordered DATE );
D.CREATE OR REPLACE TABLE orders ( order_id NUMBER(10), customer_id NUMBER(8), order_status VARCHAR2(10) = 'PENDING', date_ordered DATE );
E.CREATE TABLE orders ( order_id NUMBER(10), customer_id NUMBER(8), order_status VARCHAR2(10) DEFAULT 'PENDING', date_ordered DATE );
F.CREATE TABLE orders ( order_id NUMBER(10), customer_id NUMBER(8), order_status VARCHAR2(10) DEFAULT 'PENDING', date_ordered VARCHAR2 );
Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables:
EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2(25)
LAST_NAME VARCHAR2(25)
HIRE_DATE DATE
NEW_EMPLOYEES
EMPLOYEE_ID NUMBER Primary Key
NAME VARCHAR2(60)
Which DELETE statement is valid?（）
A.DELETE FROM employees WHERE employee_id = (SELECT employee_id FROM employees);
B.DELETE * FROM employees WHERE employee_id = (SELECT employee_id FROM new_employees);
C.DELETE FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE name ='Carrey');
D.DELETE * FROM employees WHERE employee_id IN (SELECT employee_id FROM new_employees WHERE last_name ='Carrey');
A.SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP;
B.SELECT ROUND(hire_date) FROM EMP;
C.SELECT sysdate-hire_date FROM EMP;
D.SELECT TO_NUMBER(hire_date + 7) FROM EMP;
最新试题
Which three statements about subqueries are true? （）
Which statement accomplish this? （）
Which two statements are true about constraints? （）
Which view should a user query to display the columns associated with the constraints on a table owned by the user? （）
Which are /SQL*Plus commands? （）
Which two are true about aggregate functions?（）
Which statement correctly describes SQL and /SQL*Plus? （）
Which two statements about subqueries are true? （）
You need to design a student registration database that contains several tables storing academic information.The STUDENTS table stores information about a student. The STUDENT_GRADES table storesinformation about the student's grades. Both of the tables have a column named STUDENT_ID. The STUDENT_ID column in the STUDENTS table is a primary key.You need to create a foreign key on the STUDENT_ID column of the STUDENT_GRADES table thatpoints to the STUDENT_ID column of the STUDENTS table. Which statement creates the foreign key?（）
Which four are types of functions available in SQL? （）